Snippets of a simple Vaadn 7 component extension that should ensure numeric-only characters entered in a text field, using jQuery + the autoNumeric jQuery plugin. autoNumeric is very flexible - I haven't done any configuration, but it's not very difficult to do.

AutoNumericExtension.java

/**
 * An extension used to configure a TextField to allow only numbers, using the autoNumeric jQuery plugin.
 *
 * Proof of concept, really : have not implemented any server side configuration.
 * <p/>
 *
 * @author Charles
 * @see <a href="http://www.decorplanit.com/plugin">autoNumeric site</a>
 * @see <a href="https://jquery.org">jQuery site</a>
 */
@JavaScript({"js/jquery-1.8.3.min.js", "js/autoNumeric-1.9.6.js"})
public class AutoNumericExtension extends AbstractExtension {

  private static final long serialVersionUID = 8976627065068505781L;

  public void extend(AbstractTextField target) {
    super.extend(target);
  }
}

AutoNumericExtensionConnector.java

@Connect(AutoNumericExtension.class)
public class AutoNumericExtensionConnector extends AbstractExtensionConnector {
  private static final long serialVersionUID = 6875456486902748081L;

  protected transient VTextField textFieldWidget;

  @Override
  protected void extend(ServerConnector target) {
    textFieldWidget = (VTextField) ((ComponentConnector) target).getWidget();
    initAutoNumeric(textFieldWidget.getElement());
  }

  protected static native void initAutoNumeric(Element element)
     /*-{
         $wnd.jQuery(element).autoNumeric('init');
     }-*/;
}

Sample Use

TextField x = new TextField("Numeric Thing");
new AutoNumericExtension().extend(x);